Code:
/* LCD driver routines
CodeVisionAVR C Compiler
(C) 1998-2004 Pavel Haiduc, HP InfoTech S.R.L.
*/
#asm
.equ __lcd_direction=__lcd_port-1
.equ __lcd_pin=__lcd_port-2
.equ __lcd_rs=0
.equ __lcd_rd=1
.equ __lcd_enable=2
.equ __lcd_busy_flag=7
#endasm
#pragma used+
static unsigned char _base_y[4]={0x80,0xc0};
unsigned char _lcd_x,_lcd_y,_lcd_maxx;
#pragma used-
void _lcd_ready(void)
{
#asm
in r26,__lcd_direction
andi r26,0xf ;set as input
out __lcd_direction,r26
sbi __lcd_port,__lcd_rd ;RD=1
cbi __lcd_port,__lcd_rs ;RS=0
__lcd_busy:
rcall __lcd_delay
sbi __lcd_port,__lcd_enable ;EN=1
rcall __lcd_delay
in r26,__lcd_pin
cbi __lcd_port,__lcd_enable ;EN=0
rcall __lcd_delay
sbi __lcd_port,__lcd_enable ;EN=1
rcall __lcd_delay
cbi __lcd_port,__lcd_enable ;EN=0
sbrc r26,__lcd_busy_flag
rjmp __lcd_busy
#endasm
}
#asm
__lcd_write_nibble:
andi r26,0xf0
or r26,r27
out __lcd_port,r26 ;write
sbi __lcd_port,__lcd_enable ;EN=1
rcall __lcd_delay
cbi __lcd_port,__lcd_enable ;EN=0
__lcd_delay:
ldi r31,15
__lcd_delay0:
dec r31
brne __lcd_delay0
ret
#endasm
void _lcd_write_data(unsigned char data)
{
#asm
cbi __lcd_port,__lcd_rd ;RD=0
in r26,__lcd_direction
ori r26,0xf7 ;set as output
out __lcd_direction,r26
in r27,__lcd_port
andi r27,0xf
ld r26,y
rcall __lcd_write_nibble ;RD=0, write MSN
ld r26,y
swap r26
rcall __lcd_write_nibble ;write LSN
sbi __lcd_port,__lcd_rd ;RD=1
#endasm
}
/* write a byte to the LCD character generator or display RAM */
#if funcused lcd_write_byte
void lcd_write_byte(unsigned char addr, unsigned char data)
{
_lcd_ready();
_lcd_write_data(addr);
_lcd_ready();
#asm
sbi __lcd_port,__lcd_rs ;RS=1
#endasm
_lcd_write_data(data);
}
#endif
#if funcused lcd_read_byte || funcused lcd_init
#asm
__lcd_read_nibble:
sbi __lcd_port,__lcd_enable ;EN=1
rcall __lcd_delay
in r30,__lcd_pin ;read
cbi __lcd_port,__lcd_enable ;EN=0
rcall __lcd_delay
andi r30,0xf0
ret
#endasm
static unsigned char lcd_read_byte0(void)
{
#asm
rcall __lcd_delay
rcall __lcd_read_nibble ;read MSN
mov r26,r30
rcall __lcd_read_nibble ;read LSN
cbi __lcd_port,__lcd_rd ;RD=0
swap r30
or r30,r26
#endasm
}
#endif
#if funcused lcd_read_byte
/* read a byte from the LCD character generator or display RAM */
unsigned char lcd_read_byte(unsigned char addr)
{
_lcd_ready();
_lcd_write_data(addr);
_lcd_ready();
#asm
in r26,__lcd_direction
andi r26,0xf ;set as input
out __lcd_direction,r26
sbi __lcd_port,__lcd_rs ;RS=1
#endasm
return lcd_read_byte0();
}
#endif
/* set the LCD display position x=0..39 y=0..3 */
#if funcused lcd_gotoxy || funcused lcd_putchar || funcused lcd_puts || funcused lcd_putsf
void lcd_gotoxy(unsigned char x, unsigned char y)
{
_lcd_ready(); // RS=0
_lcd_write_data(_base_y[y]+x+0x80);
_lcd_x=x;
_lcd_y=y;
}
#endif
// clear the LCD
#if funcused lcd_clear || funcused lcd_init
void lcd_clear(void)
{
_lcd_ready(); // RS=0
_lcd_write_data(2); // cursor home
_lcd_ready();
_lcd_write_data(0xc); // cursor off
_lcd_ready();
_lcd_write_data(1); // clear
_lcd_x=_lcd_y=0;
}
#endif
#if funcused lcd_putchar || funcused lcd_puts || funcused lcd_putsf
#pragma keep+
void lcd_putchar(char c)
{
#asm
push r30
push r31
ld r26,y
set
cpi r26,10
breq __lcd_putchar1
clt
#endasm
++_lcd_x;
if (_lcd_x>_lcd_maxx)
{
#asm("__lcd_putchar1:")
++_lcd_y;
lcd_gotoxy(0,_lcd_y);
#asm("brts __lcd_putchar0")
};
#asm
rcall __lcd_ready
sbi __lcd_port,__lcd_rs ;RS=1
ld r26,y
st -y,r26
rcall __lcd_write_data
__lcd_putchar0:
pop r31
pop r30
#endasm
}
#pragma keep-
#endif
// write the string str located in SRAM to the LCD
#if funcused lcd_puts
void lcd_puts(char *str)
{
#ifdef _MODEL_TINY_
#asm
clr r31
#endasm
#endif
#ifdef _MODEL_SMALL_
#asm
ldd r31,y+1
#endasm
#endif
#asm
ld r30,y
__lcd_puts0:
ld r26,z+
tst r26
breq __lcd_puts1
st -y,r26
rcall _lcd_putchar
rjmp __lcd_puts0
__lcd_puts1:
#endasm
}
#endif
// write the string str located in FLASH to the LCD
#if funcused lcd_putsf
void lcd_putsf(char flash *str)
{
#asm
ld r30,y
ldd r31,y+1
__lcd_putsf0:
#endasm
#if defined _CHIP_ATMEGA128_ || defined _CHIP_ATMEGA128L_
#asm("elpm")
#else
#asm("lpm")
#endif
#asm
tst r0
breq __lcd_putsf1
adiw r30,1
st -y,r0
rcall _lcd_putchar
rjmp __lcd_putsf0
__lcd_putsf1:
#endasm
}
#endif
#if funcused lcd_init
static void _long_delay(void)
{
#asm
clr r26
clr r27
__long_delay0:
sbiw r26,1 ;2 cycles
brne __long_delay0 ;2 cycles
#endasm
}
static void _lcd_init_write(unsigned char data)
{
#asm
cbi __lcd_port,__lcd_rd ;RD=0
in r26,__lcd_direction
ori r26,0xf7 ;set as output
out __lcd_direction,r26
in r27,__lcd_port
andi r27,0xf
ld r26,y
rcall __lcd_write_nibble ;RD=0, write MSN
ld r26,y
swap r26
rcall __lcd_write_nibble ;write LSN
sbi __lcd_port,__lcd_rd ;RD=1
#endasm
}
// initialize the LCD controller
unsigned char lcd_init (unsigned char lcd_columns)
{
#asm
cbi __lcd_port,__lcd_enable ;EN=0
cbi __lcd_port,__lcd_rs ;RS=0
#endasm
_lcd_maxx=lcd_columns;
_base_y[0]=0x00;
_base_y[1]=lcd_columns + 0x0C;
_base_y[2]=lcd_columns + 0x2C;
_base_y[3]=lcd_columns + 0x4C;
_long_delay();
_long_delay();
_lcd_init_write(0x20); // 4 Bit Modus + RE Bit clear
_long_delay();
_lcd_init_write(0x24); // 4 Bit Modus + RE Bit set
_long_delay();
_lcd_init_write(0x09);
_long_delay();
_lcd_init_write(0x20); // 4 Bit Modus + RE Bit clear
_long_delay();
_lcd_init_write(0x0C); // Display On
_long_delay();
_lcd_init_write(0x01); // Clear Display
_long_delay();
_lcd_init_write(0x06); //Auto Increment on
_long_delay();
#asm
in r26,__lcd_direction
andi r26,0xf ;set as input
out __lcd_direction,r26
sbi __lcd_port,__lcd_rd ;RD=1
#endasm
if (lcd_read_byte0()!=5) return 0;
_lcd_ready();
_lcd_write_data(6);
lcd_clear();
return 1;
}
#endif
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